2 files changed, 38 insertions, 21 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index af190ceab971..e0bd2235296b 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -42,7 +42,10 @@ struct page {
                                          * to show when page is mapped
                                          * & limit reverse map searches.
                                          */
-                unsigned int inuse;     /* SLUB: Nr of objects */
+                struct {                /* SLUB */
+                        u16 inuse;
+                        u16 objects;
+                };
         };
         union {
             struct {
diff --git a/mm/slub.c b/mm/slub.c
index 64c2b2bfbd79..6641025c597f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -301,7 +301,7 @@ static inline int check_valid_pointer(struct kmem_cache *s,
                 return 1;
 
         base = page_address(page);
-        if (object < base || object >= base + s->objects * s->size ||
+        if (object < base || object >= base + page->objects * s->size ||
                 (object - base) % s->size) {
                 return 0;
         }
@@ -451,8 +451,8 @@ static void print_tracking(struct kmem_cache *s, void *object)
 
 static void print_page_info(struct page *page)
 {
-        printk(KERN_ERR "INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n",
-                page, page->inuse, page->freelist, page->flags);
+        printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
+                page, page->objects, page->inuse, page->freelist, page->flags);
 
 }
 
@@ -652,6 +652,7 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
                                 p + off, POISON_INUSE, s->size - off);
 }
 
+/* Check the pad bytes at the end of a slab page */
 static int slab_pad_check(struct kmem_cache *s, struct page *page)
 {
         u8 *start;
@@ -664,20 +665,20 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
                 return 1;
 
         start = page_address(page);
-        end = start + (PAGE_SIZE << s->order);
-        length = s->objects * s->size;
-        remainder = end - (start + length);
+        length = (PAGE_SIZE << s->order);
+        end = start + length;
+        remainder = length % s->size;
         if (!remainder)
                 return 1;
 
-        fault = check_bytes(start + length, POISON_INUSE, remainder);
+        fault = check_bytes(end - remainder, POISON_INUSE, remainder);
         if (!fault)
                 return 1;
         while (end > fault && end[-1] == POISON_INUSE)
                 end--;
 
         slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
-        print_section("Padding", start, length);
+        print_section("Padding", end - remainder, remainder);
 
         restore_bytes(s, "slab padding", POISON_INUSE, start, end);
         return 0;
@@ -739,15 +740,24 @@ static int check_object(struct kmem_cache *s, struct page *page,
 
 static int check_slab(struct kmem_cache *s, struct page *page)
 {
+        int maxobj;
+
         VM_BUG_ON(!irqs_disabled());
 
         if (!PageSlab(page)) {
                 slab_err(s, page, "Not a valid slab page");
                 return 0;
         }
-        if (page->inuse > s->objects) {
+
+        maxobj = (PAGE_SIZE << compound_order(page)) / s->size;
+        if (page->objects > maxobj) {
+                slab_err(s, page, "objects %u > max %u",
+                        s->name, page->objects, maxobj);
+                return 0;
+        }
+        if (page->inuse > page->objects) {
                 slab_err(s, page, "inuse %u > max %u",
-                        s->name, page->inuse, s->objects);
+                        s->name, page->inuse, page->objects);
                 return 0;
         }
         /* Slab_pad_check fixes things up after itself */
@@ -765,7 +775,7 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
         void *fp = page->freelist;
         void *object = NULL;
 
-        while (fp && nr <= s->objects) {
+        while (fp && nr <= page->objects) {
                 if (fp == search)
                         return 1;
                 if (!check_valid_pointer(s, page, fp)) {
@@ -777,7 +787,7 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
                         } else {
                                 slab_err(s, page, "Freepointer corrupt");
                                 page->freelist = NULL;
-                                page->inuse = s->objects;
+                                page->inuse = page->objects;
                                 slab_fix(s, "Freelist cleared");
                                 return 0;
                         }
@@ -788,10 +798,10 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
                 nr++;
         }
 
-        if (page->inuse != s->objects - nr) {
+        if (page->inuse != page->objects - nr) {
                 slab_err(s, page, "Wrong object count. Counter is %d but "
-                        "counted were %d", page->inuse, s->objects - nr);
-                page->inuse = s->objects - nr;
+                        "counted were %d", page->inuse, page->objects - nr);
+                page->inuse = page->objects - nr;
                 slab_fix(s, "Object count adjusted.");
         }
         return search == NULL;
@@ -910,7 +920,7 @@ bad:
                  * as used avoids touching the remaining objects.
                  */
                 slab_fix(s, "Marking all objects used");
-                page->inuse = s->objects;
+                page->inuse = page->objects;
                 page->freelist = NULL;
         }
         return 0;
@@ -1081,6 +1091,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
         if (!page)
                 return NULL;
 
+        page->objects = s->objects;
         mod_zone_page_state(page_zone(page),
                 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
                 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
@@ -1519,7 +1530,7 @@ load_freelist:
                 goto debug;
 
         c->freelist = object[c->offset];
-        c->page->inuse = s->objects;
+        c->page->inuse = c->page->objects;
         c->page->freelist = NULL;
         c->node = page_to_nid(c->page);
 unlock_out:
@@ -1818,6 +1829,9 @@ static inline int slab_order(int size, int min_objects,
         int rem;
         int min_order = slub_min_order;
 
+        if ((PAGE_SIZE << min_order) / size > 65535)
+                return get_order(size * 65535) - 1;
+
         for (order = max(min_order,
                                 fls(min_objects * size - 1) - PAGE_SHIFT);
                         order <= max_order; order++) {
@@ -3251,7 +3265,7 @@ static int validate_slab(struct kmem_cache *s, struct page *page,
                 return 0;
 
         /* Now we know that a valid freelist exists */
-        bitmap_zero(map, s->objects);
+        bitmap_zero(map, page->objects);
 
         for_each_free_object(p, s, page->freelist) {
                 set_bit(slab_index(p, s, addr), map);
@@ -3528,10 +3542,10 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s,
                 struct page *page, enum track_item alloc)
 {
         void *addr = page_address(page);
-        DECLARE_BITMAP(map, s->objects);
+        DECLARE_BITMAP(map, page->objects);
         void *p;
 
-        bitmap_zero(map, s->objects);
+        bitmap_zero(map, page->objects);
         for_each_free_object(p, s, page->freelist)
                 set_bit(slab_index(p, s, addr), map);